Your profile picture is how the online world perceive you, so make it a good one. The folks at Photo Feeler surveyed 60,000 ratings of 800 profile photos and came up with a few rules to look good, like "squinching" your eyes and smiling with your teeth showing.

The gist of the concept is this: wide open eyes commonly denote fear, whereas slightly squinted eyes portray comfort and confidence. As a consequence, squinching eyes garner an average gain of +0.33 for Competence, +0.22 for Likability, and +0.37 for Influence.

The research found other useful patterns in making a good profile photo. For instance, a shot of your bust (head and shoulders) or torso (head to waist) score high, while face-only shots or full-body photos are not preferable. Photo Feeler put all the information in this helpful infographic, but you should check out the link for an explanation of each aspect.